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The GDB/MI Interface

Function and Purpose

GDB/MI is a line based machine oriented text interface to GDB and is activated by specifying using the @option{--interpreter} command line option (see section Choosing modes). It is specifically intended to support the development of systems which use the debugger as just one small component of a larger system.

This chapter is a specification of the GDB/MI interface. It is written in the form of a reference manual.

Note that GDB/MI is still under construction, so some of the features described below are incomplete and subject to change.

Notation and Terminology

This chapter uses the following notation:

Acknowledgments

In alphabetic order: Andrew Cagney, Fernando Nasser, Stan Shebs and Elena Zannoni.

GDB/MI Command Syntax

GDB/MI Input Syntax

command ==>
cli-command | mi-command
cli-command ==>
[ token ] cli-command nl, where cli-command is any existing GDB CLI command.
mi-command ==>
[ token ] "-" operation ( " " option )* [ " --" ] ( " " parameter )* nl
token ==>
"any sequence of digits"
option ==>
"-" parameter [ " " parameter ]
parameter ==>
non-blank-sequence | c-string
operation ==>
any of the operations described in this chapter
non-blank-sequence ==>
anything, provided it doesn't contain special characters such as "-", nl, """ and of course " "
c-string ==>
""" seven-bit-iso-c-string-content """
nl ==>
CR | CR-LF

Notes:

Pragmatics:

GDB/MI Output Syntax

The output from GDB/MI consists of zero or more out-of-band records followed, optionally, by a single result record. This result record is for the most recent command. The sequence of output records is terminated by `(gdb)'.

If an input command was prefixed with a token then the corresponding output for that command will also be prefixed by that same token.

output ==>
( out-of-band-record )* [ result-record ] "(gdb)" nl
result-record ==>
[ token ] "^" result-class ( "," result )* nl
out-of-band-record ==>
async-record | stream-record
async-record ==>
exec-async-output | status-async-output | notify-async-output
exec-async-output ==>
[ token ] "*" async-output
status-async-output ==>
[ token ] "+" async-output
notify-async-output ==>
[ token ] "=" async-output
async-output ==>
async-class ( "," result )* nl
result-class ==>
"done" | "running" | "connected" | "error" | "exit"
async-class ==>
"stopped" | others (where others will be added depending on the needs--this is still in development).
result ==>
variable "=" value
variable ==>
string
value ==>
const | tuple | list
const ==>
c-string
tuple ==>
"{}" | "{" result ( "," result )* "}"
list ==>
"[]" | "[" value ( "," value )* "]" | "[" result ( "," result )* "]"
stream-record ==>
console-stream-output | target-stream-output | log-stream-output
console-stream-output ==>
"~" c-string
target-stream-output ==>
"@" c-string
log-stream-output ==>
"&" c-string
nl ==>
CR | CR-LF
token ==>
any sequence of digits.

Notes:

See section GDB/MI Stream Records, for more details about the various output records.

Simple Examples of GDB/MI Interaction

This subsection presents several simple examples of interaction using the GDB/MI interface. In these examples, `->' means that the following line is passed to GDB/MI as input, while `<-' means the output received from GDB/MI.

Target Stop

Here's an example of stopping the inferior process:

-> -stop
<- (gdb)

and later:

<- *stop,reason="stop",address="0x123",source="a.c:123"
<- (gdb)

Simple CLI Command

Here's an example of a simple CLI command being passed through GDB/MI and on to the CLI.

-> print 1+2
<- &"print 1+2\n"
<- ~"$1 = 3\n"
<- ^done
<- (gdb)

Command With Side Effects

-> -symbol-file xyz.exe
<- *breakpoint,nr="3",address="0x123",source="a.c:123"
<- (gdb)

A Bad Command

Here's what happens if you pass a non-existent command:

-> -rubbish
<- ^error,msg="Undefined MI command: rubbish"
<- (gdb)

GDB/MI Compatibility with CLI

To help users familiar with GDB's existing CLI interface, GDB/MI accepts existing CLI commands. As specified by the syntax, such commands can be directly entered into the GDB/MI interface and GDB will respond.

This mechanism is provided as an aid to developers of GDB/MI clients and not as a reliable interface into the CLI. Since the command is being interpreteted in an environment that assumes GDB/MI behaviour, the exact output of such commands is likely to end up being an un-supported hybrid of GDB/MI and CLI output.

GDB/MI Output Records

GDB/MI Result Records

In addition to a number of out-of-band notifications, the response to a GDB/MI command includes one of the following result indications:

"^done" [ "," results ]
The synchronous operation was successful, results are the return values.
"^running"
The asynchronous operation was successfully started. The target is running.
"^error" "," c-string
The operation failed. The c-string contains the corresponding error message.

GDB/MI Stream Records

GDB internally maintains a number of output streams: the console, the target, and the log. The output intended for each of these streams is funneled through the GDB/MI interface using stream records.

Each stream record begins with a unique prefix character which identifies its stream (see section GDB/MI Output Syntax). In addition to the prefix, each stream record contains a string-output. This is either raw text (with an implicit new line) or a quoted C string (which does not contain an implicit newline).

"~" string-output
The console output stream contains text that should be displayed in the CLI console window. It contains the textual responses to CLI commands.
"@" string-output
The target output stream contains any textual output from the running target.
"&" string-output
The log stream contains debugging messages being produced by GDB's internals.

GDB/MI Out-of-band Records

Out-of-band records are used to notify the GDB/MI client of additional changes that have occurred. Those changes can either be a consequence of GDB/MI (e.g., a breakpoint modified) or a result of target activity (e.g., target stopped).

The following is a preliminary list of possible out-of-band records. In particular, the exec-async-output records.

*stopped,reason="reason"

reason can be one of the following:

breakpoint-hit
A breakpoint was reached.
watchpoint-trigger
A watchpoint was triggered.
read-watchpoint-trigger
A read watchpoint was triggered.
access-watchpoint-trigger
An access watchpoint was triggered.
function-finished
An -exec-finish or similar CLI command was accomplished.
location-reached
An -exec-until or similar CLI command was accomplished.
watchpoint-scope
A watchpoint has gone out of scope.
end-stepping-range
An -exec-next, -exec-next-instruction, -exec-step, -exec-step-instruction or similar CLI command was accomplished.
exited-signalled
The inferior exited because of a signal.
exited
The inferior exited.
exited-normally
The inferior exited normally.
signal-received
A signal was received by the inferior.

GDB/MI Command Description Format

The remaining sections describe blocks of commands. Each block of commands is laid out in a fashion similar to this section.

Note the the line breaks shown in the examples are here only for readability. They don't appear in the real output. Also note that the commands with a non-available example (N.A.) are not yet implemented.

Motivation

The motivation for this collection of commands.

Introduction

A brief introduction to this collection of commands as a whole.

Commands

For each command in the block, the following is described:

Synopsis

 -command args...

Result

GDB Command

The corresponding GDB CLI command(s), if any.

Example

GDB/MI Breakpoint table commands

This section documents GDB/MI commands for manipulating breakpoints.

The -break-after Command

Synopsis

 -break-after number count

The breakpoint number number is not in effect until it has been hit count times. To see how this is reflected in the output of the `-break-list' command, see the description of the `-break-list' command below.

GDB Command

The corresponding GDB command is `ignore'.

Example

(gdb)
-break-insert main
^done,bkpt={number="1",addr="0x000100d0",file="hello.c",line="5"}
(gdb)
-break-after 1 3
~
^done
(gdb)
-break-list
^done,BreakpointTable={nr_rows="1",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",
addr="0x000100d0",func="main",file="hello.c",line="5",times="0",
ignore="3"}]}
(gdb)

The -break-condition Command

Synopsis

 -break-condition number expr

Breakpoint number will stop the program only if the condition in expr is true. The condition becomes part of the `-break-list' output (see the description of the `-break-list' command below).

GDB Command

The corresponding GDB command is `condition'.

Example

(gdb)
-break-condition 1 1
^done
(gdb)
-break-list
^done,BreakpointTable={nr_rows="1",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",
addr="0x000100d0",func="main",file="hello.c",line="5",cond="1",
times="0",ignore="3"}]}
(gdb)

The -break-delete Command

Synopsis

 -break-delete ( breakpoint )+

Delete the breakpoint(s) whose number(s) are specified in the argument list. This is obviously reflected in the breakpoint list.

GDB command

The corresponding GDB command is `delete'.

Example

(gdb)
-break-delete 1
^done
(gdb)
-break-list
^done,BreakpointTable={nr_rows="0",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[]}
(gdb)

The -break-disable Command

Synopsis

 -break-disable ( breakpoint )+

Disable the named breakpoint(s). The field `enabled' in the break list is now set to `n' for the named breakpoint(s).

GDB Command

The corresponding GDB command is `disable'.

Example

(gdb)
-break-disable 2
^done
(gdb)
-break-list
^done,BreakpointTable={nr_rows="1",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="2",type="breakpoint",disp="keep",enabled="n",
addr="0x000100d0",func="main",file="hello.c",line="5",times="0"}]}
(gdb)

The -break-enable Command

Synopsis

 -break-enable ( breakpoint )+

Enable (previously disabled) breakpoint(s).

GDB Command

The corresponding GDB command is `enable'.

Example

(gdb)
-break-enable 2
^done
(gdb)
-break-list
^done,BreakpointTable={nr_rows="1",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="2",type="breakpoint",disp="keep",enabled="y",
addr="0x000100d0",func="main",file="hello.c",line="5",times="0"}]}
(gdb)

The -break-info Command

Synopsis

 -break-info breakpoint

Get information about a single breakpoint.

GDB command

The corresponding GDB command is `info break breakpoint'.

Example

N.A.

The -break-insert Command

Synopsis

 -break-insert [ -t ] [ -h ] [ -r ]
    [ -c condition ] [ -i ignore-count ]
    [ -p thread ] [ line | addr ]
    [-l [ <NUM> <NUM>...] ]

If specified, line, can be one of:

The possible optional parameters of this command are:

`-t'
Insert a tempoary breakpoint.
`-h'
Insert a hardware breakpoint.
`-c condition'
Make the breakpoint conditional on condition.
`-i ignore-count'
Initialize the ignore-count.
`-r'
Insert a regular breakpoint in all the functions whose names match the given regular expression. Other flags are not applicable to regular expresson.
`-l [<NUM> <NUM>...]'
This list of indices will be used to select from the list of matches if there are multiple breakpoint hits. Passing -1 will cause all matches to be selected.

Result

The result is in the form:

 ^done,bkptno="number",func="funcname",
  file="filename",line="lineno",shlib="shlib"

or, if there are multiple breakpoints, and the -l option is not selected:

 ^done,matches=[b=[index="index",number="number",func="funcname",
  file="filename",line="lineno"], b=[]...]

where number is the GDB number for this breakpoint, funcname is the name of the function where the breakpoint was inserted, filename is the name of the source file which contains this function, and lineno is the source line number within that file, and shlib is the shared library in which the breakpoint was set.

If there are multiple matches, the second form is sent including the index element, and no breakpoints are set. This will allow the UI to put up some kind of picker. Then it can re-issue the command with the -l option, using the index values provided by the first result. If you just want multiple matches to be always selected, then send a selection list of -1 always.

Note: this format is open to change.

GDB Command

The corresponding GDB commands are `break', `tbreak', `hbreak', `thbreak', and `rbreak'.

Example

(gdb)
-break-insert main
^done,bkpt={number="1",addr="0x0001072c",file="recursive2.c",line="4"}
(gdb)
-break-insert -t foo
^done,bkpt={number="2",addr="0x00010774",file="recursive2.c",line="11"}
(gdb)
-break-list
^done,BreakpointTable={nr_rows="2",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",
addr="0x0001072c", func="main",file="recursive2.c",line="4",times="0"},
bkpt={number="2",type="breakpoint",disp="del",enabled="y",
addr="0x00010774",func="foo",file="recursive2.c",line="11",times="0"}]}
(gdb)
-break-insert -r foo.*
~int foo(int, int);
^done,bkpt={number="3",addr="0x00010774",file="recursive2.c",line="11"}
(gdb)

The -break-list Command

Synopsis

 -break-list

Displays the list of inserted breakpoints, showing the following fields:

`Number'
number of the breakpoint
`Type'
type of the breakpoint: `breakpoint' or `watchpoint'
`Disposition'
should the breakpoint be deleted or disabled when it is hit: `keep' or `nokeep'
`Enabled'
is the breakpoint enabled or no: `y' or `n'
`Address'
memory location at which the breakpoint is set
`What'
logical location of the breakpoint, expressed by function name, file name, line number
`Times'
number of times the breakpoint has been hit

If there are no breakpoints or watchpoints, the BreakpointTable body field is an empty list.

GDB Command

The corresponding GDB command is `info break'.

Example

(gdb)
-break-list
^done,BreakpointTable={nr_rows="2",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",
addr="0x000100d0",func="main",file="hello.c",line="5",times="0"},
bkpt={number="2",type="breakpoint",disp="keep",enabled="y",
addr="0x00010114",func="foo",file="hello.c",line="13",times="0"}]}
(gdb)

Here's an example of the result when there are no breakpoints:

(gdb)
-break-list
^done,BreakpointTable={nr_rows="0",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[]}
(gdb)

The -break-watch Command

Synopsis

 -break-watch [ -a | -r ]

Create a watchpoint. With the `-a' option it will create an access watchpoint, i.e. a watchpoint that triggers either on a read from or on a write to the memory location. With the `-r' option, the watchpoint created is a read watchpoint, i.e. it will trigger only when the memory location is accessed for reading. Without either of the options, the watchpoint created is a regular watchpoint, i.e. it will trigger when the memory location is accessed for writing. See section Setting watchpoints.

Note that `-break-list' will report a single list of watchpoints and breakpoints inserted.

GDB Command

The corresponding GDB commands are `watch', `awatch', and `rwatch'.

Example

Setting a watchpoint on a variable in the main function:

(gdb)
-break-watch x
^done,wpt={number="2",exp="x"}
(gdb)
-exec-continue
^running
^done,reason="watchpoint-trigger",wpt={number="2",exp="x"},
value={old="-268439212",new="55"},
frame={func="main",args=[],file="recursive2.c",
fullname="/home/foo/bar/devo/myproject/recursive2.c",line="5"}
(gdb)

Setting a watchpoint on a variable local to a function. GDB will stop the program execution twice: first for the variable changing value, then for the watchpoint going out of scope.

(gdb)
-break-watch C
^done,wpt={number="5",exp="C"}
(gdb)
-exec-continue
^running
^done,reason="watchpoint-trigger",
wpt={number="5",exp="C"},value={old="-276895068",new="3"},
frame={func="callee4",args=[],
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"}
(gdb)
-exec-continue
^running
^done,reason="watchpoint-scope",wpnum="5",
frame={func="callee3",args=[{name="strarg",
value="0x11940 \"A string argument.\""}],
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"}
(gdb)

Listing breakpoints and watchpoints, at different points in the program execution. Note that once the watchpoint goes out of scope, it is deleted.

(gdb)
-break-watch C
^done,wpt={number="2",exp="C"}
(gdb)
-break-list
^done,BreakpointTable={nr_rows="2",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",
addr="0x00010734",func="callee4",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"},
bkpt={number="2",type="watchpoint",disp="keep",
enabled="y",addr="",what="C",times="0"}]}
(gdb)
-exec-continue
^running
^done,reason="watchpoint-trigger",wpt={number="2",exp="C"},
value={old="-276895068",new="3"},
frame={func="callee4",args=[],
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"}
(gdb)
-break-list
^done,BreakpointTable={nr_rows="2",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",
addr="0x00010734",func="callee4",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"},
bkpt={number="2",type="watchpoint",disp="keep",
enabled="y",addr="",what="C",times="-5"}]}
(gdb)
-exec-continue
^running
^done,reason="watchpoint-scope",wpnum="2",
frame={func="callee3",args=[{name="strarg",
value="0x11940 \"A string argument.\""}],
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"}
(gdb)
-break-list
^done,BreakpointTable={nr_rows="1",nr_cols="6",
hdr=[{width="3",alignment="-1",col_name="number",colhdr="Num"},
{width="14",alignment="-1",col_name="type",colhdr="Type"},
{width="4",alignment="-1",col_name="disp",colhdr="Disp"},
{width="3",alignment="-1",col_name="enabled",colhdr="Enb"},
{width="10",alignment="-1",col_name="addr",colhdr="Address"},
{width="40",alignment="2",col_name="what",colhdr="What"}],
body=[bkpt={number="1",type="breakpoint",disp="keep",enabled="y",
addr="0x00010734",func="callee4",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"}]}
(gdb)

GDB/MI Data Manipulation

This section describes the GDB/MI commands that manipulate data: examine memory and registers, evaluate expressions, etc.

The -data-disassemble Command

Synopsis

 -data-disassemble
    [ -s start-addr -e end-addr ]
  | [ -f filename -l linenum [ -n lines ] ]
  -- mode

Where:

`start-addr'
is the beginning address (or $pc)
`end-addr'
is the end address
`filename'
is the name of the file to disassemble
`linenum'
is the line number to disassemble around
`lines'
is the the number of disassembly lines to be produced. If it is -1, the whole function will be disassembled, in case no end-addr is specified. If end-addr is specified as a non-zero value, and lines is lower than the number of disassembly lines between start-addr and end-addr, only lines lines are displayed; if lines is higher than the number of lines between start-addr and end-addr, only the lines up to end-addr are displayed.
`mode'
is either 0 (meaning only disassembly) or 1 (meaning mixed source and disassembly).

Result

The output for each instruction is composed of four fields:

Note that whatever included in the instruction field, is not manipulated directely by GDB/MI, i.e. it is not possible to adjust its format.

GDB Command

There's no direct mapping from this command to the CLI.

Example

Disassemble from the current value of $pc to $pc + 20:

(gdb)
-data-disassemble -s $pc -e "$pc + 20" -- 0
^done,
asm_insns=[
{address="0x000107c0",func-name="main",offset="4",
inst="mov  2, %o0"},
{address="0x000107c4",func-name="main",offset="8",
inst="sethi  %hi(0x11800), %o2"},
{address="0x000107c8",func-name="main",offset="12",
inst="or  %o2, 0x140, %o1\t! 0x11940 <_lib_version+8>"},
{address="0x000107cc",func-name="main",offset="16",
inst="sethi  %hi(0x11800), %o2"},
{address="0x000107d0",func-name="main",offset="20",
inst="or  %o2, 0x168, %o4\t! 0x11968 <_lib_version+48>"}]
(gdb)

Disassemble the whole main function. Line 32 is part of main.

-data-disassemble -f basics.c -l 32 -- 0
^done,asm_insns=[
{address="0x000107bc",func-name="main",offset="0",
inst="save  %sp, -112, %sp"},
{address="0x000107c0",func-name="main",offset="4",
inst="mov   2, %o0"},
{address="0x000107c4",func-name="main",offset="8",
inst="sethi %hi(0x11800), %o2"},
[...]
{address="0x0001081c",func-name="main",offset="96",inst="ret "},
{address="0x00010820",func-name="main",offset="100",inst="restore "}]
(gdb)

Disassemble 3 instructions from the start of main:

(gdb)
-data-disassemble -f basics.c -l 32 -n 3 -- 0
^done,asm_insns=[
{address="0x000107bc",func-name="main",offset="0",
inst="save  %sp, -112, %sp"},
{address="0x000107c0",func-name="main",offset="4",
inst="mov  2, %o0"},
{address="0x000107c4",func-name="main",offset="8",
inst="sethi  %hi(0x11800), %o2"}]
(gdb)

Disassemble 3 instructions from the start of main in mixed mode:

(gdb)
-data-disassemble -f basics.c -l 32 -n 3 -- 1
^done,asm_insns=[
src_and_asm_line={line="31",
file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \
  testsuite/gdb.mi/basics.c",line_asm_insn=[
{address="0x000107bc",func-name="main",offset="0",
inst="save  %sp, -112, %sp"}]},
src_and_asm_line={line="32",
file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \
  testsuite/gdb.mi/basics.c",line_asm_insn=[
{address="0x000107c0",func-name="main",offset="4",
inst="mov  2, %o0"},
{address="0x000107c4",func-name="main",offset="8",
inst="sethi  %hi(0x11800), %o2"}]}]
(gdb)

The -data-evaluate-expression Command

Synopsis

 -data-evaluate-expression expr

Evaluate expr as an expression. The expression could contain an inferior function call. The function call will execute synchronously. If the expression contains spaces, it must be enclosed in double quotes.

GDB Command

The corresponding GDB commands are `print', `output', and `call'. In gdbtk only, there's a corresponding `gdb_eval' command.

Example

In the following example, the numbers that precede the commands are the tokens described in section GDB/MI Command Syntax. Notice how GDB/MI returns the same tokens in its output.

211-data-evaluate-expression A
211^done,value="1"
(gdb)
311-data-evaluate-expression &A
311^done,value="0xefffeb7c"
(gdb)
411-data-evaluate-expression A+3
411^done,value="4"
(gdb)
511-data-evaluate-expression "A + 3"
511^done,value="4"
(gdb)

The -data-list-changed-registers Command

Synopsis

 -data-list-changed-registers

Display a list of the registers that have changed.

GDB Command

GDB doesn't have a direct analog for this command; gdbtk has the corresponding command `gdb_changed_register_list'.

Example

On a PPC MBX board:

(gdb)
-exec-continue
^running

(gdb)
*stopped,reason="breakpoint-hit",bkptno="1",frame={func="main",
args=[],file="try.c",fullname="/home/foo/bar/devo/myproject/try.c",line="5"}
(gdb)
-data-list-changed-registers
^done,changed-registers=["0","1","2","4","5","6","7","8","9",
"10","11","13","14","15","16","17","18","19","20","21","22","23",
"24","25","26","27","28","30","31","64","65","66","67","69"]
(gdb)

The -data-list-register-names Command

Synopsis

 -data-list-register-names [ ( regno )+ ]

Show a list of register names for the current target. If no arguments are given, it shows a list of the names of all the registers. If integer numbers are given as arguments, it will print a list of the names of the registers corresponding to the arguments. To ensure consistency between a register name and its number, the output list may include empty register names.

GDB Command

GDB does not have a command which corresponds to `-data-list-register-names'. In gdbtk there is a corresponding command `gdb_regnames'.

Example

For the PPC MBX board:

(gdb)
-data-list-register-names
^done,register-names=["r0","r1","r2","r3","r4","r5","r6","r7",
"r8","r9","r10","r11","r12","r13","r14","r15","r16","r17","r18",
"r19","r20","r21","r22","r23","r24","r25","r26","r27","r28","r29",
"r30","r31","f0","f1","f2","f3","f4","f5","f6","f7","f8","f9",
"f10","f11","f12","f13","f14","f15","f16","f17","f18","f19","f20",
"f21","f22","f23","f24","f25","f26","f27","f28","f29","f30","f31",
"", "pc","ps","cr","lr","ctr","xer"]
(gdb)
-data-list-register-names 1 2 3
^done,register-names=["r1","r2","r3"]
(gdb)

The -data-list-register-values Command

Synopsis

 -data-list-register-values fmt [ ( regno )*]

Display the registers' contents. fmt is the format according to which the registers' contents are to be returned, followed by an optional list of numbers specifying the registers to display. A missing list of numbers indicates that the contents of all the registers must be returned.

Allowed formats for fmt are:

x
Hexadecimal
o
Octal
t
Binary
d
Decimal
r
Raw
N
Natural

GDB Command

The corresponding GDB commands are `info reg', `info all-reg', and (in gdbtk) `gdb_fetch_registers'.

Example

For a PPC MBX board (note: line breaks are for readability only, they don't appear in the actual output):

(gdb)
-data-list-register-values r 64 65
^done,register-values=[{number="64",value="0xfe00a300"},
{number="65",value="0x00029002"}]
(gdb)
-data-list-register-values x
^done,register-values=[{number="0",value="0xfe0043c8"},
{number="1",value="0x3fff88"},{number="2",value="0xfffffffe"},
{number="3",value="0x0"},{number="4",value="0xa"},
{number="5",value="0x3fff68"},{number="6",value="0x3fff58"},
{number="7",value="0xfe011e98"},{number="8",value="0x2"},
{number="9",value="0xfa202820"},{number="10",value="0xfa202808"},
{number="11",value="0x1"},{number="12",value="0x0"},
{number="13",value="0x4544"},{number="14",value="0xffdfffff"},
{number="15",value="0xffffffff"},{number="16",value="0xfffffeff"},
{number="17",value="0xefffffed"},{number="18",value="0xfffffffe"},
{number="19",value="0xffffffff"},{number="20",value="0xffffffff"},
{number="21",value="0xffffffff"},{number="22",value="0xfffffff7"},
{number="23",value="0xffffffff"},{number="24",value="0xffffffff"},
{number="25",value="0xffffffff"},{number="26",value="0xfffffffb"},
{number="27",value="0xffffffff"},{number="28",value="0xf7bfffff"},
{number="29",value="0x0"},{number="30",value="0xfe010000"},
{number="31",value="0x0"},{number="32",value="0x0"},
{number="33",value="0x0"},{number="34",value="0x0"},
{number="35",value="0x0"},{number="36",value="0x0"},
{number="37",value="0x0"},{number="38",value="0x0"},
{number="39",value="0x0"},{number="40",value="0x0"},
{number="41",value="0x0"},{number="42",value="0x0"},
{number="43",value="0x0"},{number="44",value="0x0"},
{number="45",value="0x0"},{number="46",value="0x0"},
{number="47",value="0x0"},{number="48",value="0x0"},
{number="49",value="0x0"},{number="50",value="0x0"},
{number="51",value="0x0"},{number="52",value="0x0"},
{number="53",value="0x0"},{number="54",value="0x0"},
{number="55",value="0x0"},{number="56",value="0x0"},
{number="57",value="0x0"},{number="58",value="0x0"},
{number="59",value="0x0"},{number="60",value="0x0"},
{number="61",value="0x0"},{number="62",value="0x0"},
{number="63",value="0x0"},{number="64",value="0xfe00a300"},
{number="65",value="0x29002"},{number="66",value="0x202f04b5"},
{number="67",value="0xfe0043b0"},{number="68",value="0xfe00b3e4"},
{number="69",value="0x20002b03"}]
(gdb)

The -data-read-memory Command

Synopsis

 -data-read-memory [ -o byte-offset ]
   address word-format word-size
   nr-rows nr-cols [ aschar ]

where:

`address'
An expression specifying the address of the first memory word to be read. Complex expressions containing embedded white space should be quoted using the C convention.
`word-format'
The format to be used to print the memory words. The notation is the same as for GDB's print command (see section Output formats).
`word-size'
The size of each memory word in bytes.
`nr-rows'
The number of rows in the output table.
`nr-cols'
The number of columns in the output table.
`aschar'
If present, indicates that each row should include an ASCII dump. The value of aschar is used as a padding character when a byte is not a member of the printable ASCII character set (printable ASCII characters are those whose code is between 32 and 126, inclusively).
`byte-offset'
An offset to add to the address before fetching memory.

This command displays memory contents as a table of nr-rows by nr-cols words, each word being word-size bytes. In total, nr-rows * nr-cols * word-size bytes are read (returned as `total-bytes'). Should less than the requested number of bytes be returned by the target, the missing words are identified using `N/A'. The number of bytes read from the target is returned in `nr-bytes' and the starting address used to read memory in `addr'.

The address of the next/previous row or page is available in `next-row' and `prev-row', `next-page' and `prev-page'.

GDB Command

The corresponding GDB command is `x'. gdbtk has `gdb_get_mem' memory read command.

Example

Read six bytes of memory starting at bytes+6 but then offset by -6 bytes. Format as three rows of two columns. One byte per word. Display each word in hex.

(gdb)
9-data-read-memory -o -6 -- bytes+6 x 1 3 2
9^done,addr="0x00001390",nr-bytes="6",total-bytes="6",
next-row="0x00001396",prev-row="0x0000138e",next-page="0x00001396",
prev-page="0x0000138a",memory=[
{addr="0x00001390",data=["0x00","0x01"]},
{addr="0x00001392",data=["0x02","0x03"]},
{addr="0x00001394",data=["0x04","0x05"]}]
(gdb)

Read two bytes of memory starting at address shorts + 64 and display as a single word formatted in decimal.

(gdb)
5-data-read-memory shorts+64 d 2 1 1
5^done,addr="0x00001510",nr-bytes="2",total-bytes="2",
next-row="0x00001512",prev-row="0x0000150e",
next-page="0x00001512",prev-page="0x0000150e",memory=[
{addr="0x00001510",data=["128"]}]
(gdb)

Read thirty two bytes of memory starting at bytes+16 and format as eight rows of four columns. Include a string encoding with `x' used as the non-printable character.

(gdb)
4-data-read-memory bytes+16 x 1 8 4 x
4^done,addr="0x000013a0",nr-bytes="32",total-bytes="32",
next-row="0x000013c0",prev-row="0x0000139c",
next-page="0x000013c0",prev-page="0x00001380",memory=[
{addr="0x000013a0",data=["0x10","0x11","0x12","0x13"],ascii="xxxx"},
{addr="0x000013a4",data=["0x14","0x15","0x16","0x17"],ascii="xxxx"},
{addr="0x000013a8",data=["0x18","0x19","0x1a","0x1b"],ascii="xxxx"},
{addr="0x000013ac",data=["0x1c","0x1d","0x1e","0x1f"],ascii="xxxx"},
{addr="0x000013b0",data=["0x20","0x21","0x22","0x23"],ascii=" !\"#"},
{addr="0x000013b4",data=["0x24","0x25","0x26","0x27"],ascii="$%&'"},
{addr="0x000013b8",data=["0x28","0x29","0x2a","0x2b"],ascii="()*+"},
{addr="0x000013bc",data=["0x2c","0x2d","0x2e","0x2f"],ascii=",-./"}]
(gdb)

The -display-delete Command

Synopsis

 -display-delete number

Delete the display number.

GDB Command

The corresponding GDB command is `delete display'.

Example

N.A.

The -display-disable Command

Synopsis

 -display-disable number

Disable display number.

GDB Command

The corresponding GDB command is `disable display'.

Example

N.A.

The -display-enable Command

Synopsis

 -display-enable number

Enable display number.

GDB Command

The corresponding GDB command is `enable display'.

Example

N.A.

The -display-insert Command

Synopsis

 -display-insert expression

Display expression every time the program stops.

GDB Command

The corresponding GDB command is `display'.

Example

N.A.

The -display-list Command

Synopsis

 -display-list

List the displays. Do not show the current values.

GDB Command

The corresponding GDB command is `info display'.

Example

N.A.

The -environment-cd Command

Synopsis

 -environment-cd pathdir

Set GDB's working directory.

GDB Command

The corresponding GDB command is `cd'.

Example

(gdb)
-environment-cd /kwikemart/marge/ezannoni/flathead-dev/devo/gdb
^done
(gdb)

The -environment-directory Command

Synopsis

 -environment-directory [ -r ] [ pathdir ]+

Add directories pathdir to beginning of search path for source files. If the `-r' option is used, the search path is reset to the default search path. If directories pathdir are supplied in addition to the `-r' option, the search path is first reset and then addition occurs as normal. Multiple directories may be specified, separated by blanks. Specifying multiple directories in a single command results in the directories added to the beginning of the search path in the same order they were presented in the command. If blanks are needed as part of a directory name, double-quotes should be used around the name. In the command output, the path will show up separated by the system directory-separator character. The directory-seperator character must not be used in any directory name. If no directories are specified, the current search path is displayed.

GDB Command

The corresponding GDB command is `dir'.

Example

(gdb)
-environment-directory /kwikemart/marge/ezannoni/flathead-dev/devo/gdb
^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd"
(gdb)
-environment-directory ""
^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd"
(gdb)
-environment-directory -r /home/jjohnstn/src/gdb /usr/src
^done,source-path="/home/jjohnstn/src/gdb:/usr/src:$cdir:$cwd"
(gdb)
-environment-directory -r
^done,source-path="$cdir:$cwd"
(gdb)

The -environment-path Command

Synopsis

 -environment-path [ -r ] [ pathdir ]+

Add directories pathdir to beginning of search path for object files. If the `-r' option is used, the search path is reset to the original search path that existed at gdb start-up. If directories pathdir are supplied in addition to the `-r' option, the search path is first reset and then addition occurs as normal. Multiple directories may be specified, separated by blanks. Specifying multiple directories in a single command results in the directories added to the beginning of the search path in the same order they were presented in the command. If blanks are needed as part of a directory name, double-quotes should be used around the name. In the command output, the path will show up separated by the system directory-separator character. The directory-seperator character must not be used in any directory name. If no directories are specified, the current path is displayed.

GDB Command

The corresponding GDB command is `path'.

Example

(gdb)
-environment-path
^done,path="/usr/bin"
(gdb)
-environment-path /kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb /bin
^done,path="/kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb:/bin:/usr/bin"
(gdb)
-environment-path -r /usr/local/bin
^done,path="/usr/local/bin:/usr/bin"
(gdb)

The -environment-pwd Command

Synopsis

 -environment-pwd

Show the current working directory.

GDB command

The corresponding GDB command is `pwd'.

Example

(gdb)
-environment-pwd
^done,cwd="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb"
(gdb)

GDB/MI Program control

Program termination

As a result of execution, the inferior program can run to completion, if it doesn't encounter any breakpoints. In this case the output will include an exit code, if the program has exited exceptionally.

Examples

Program exited normally:

(gdb)
-exec-run
^running
(gdb)
x = 55
*stopped,reason="exited-normally"
(gdb)

Program exited exceptionally:

(gdb)
-exec-run
^running
(gdb)
x = 55
*stopped,reason="exited",exit-code="01"
(gdb)

Another way the program can terminate is if it receives a signal such as SIGINT. In this case, GDB/MI displays this:

(gdb)
*stopped,reason="exited-signalled",signal-name="SIGINT",
signal-meaning="Interrupt"

The -exec-abort Command

Synopsis

 -exec-abort

Kill the inferior running program.

GDB Command

The corresponding GDB command is `kill'.

Example

N.A.

The -exec-arguments Command

Synopsis

 -exec-arguments args

Set the inferior program arguments, to be used in the next `-exec-run'.

GDB Command

The corresponding GDB command is `set args'.

Example

Don't have one around.

The -exec-continue Command

Synopsis

 -exec-continue

Asynchronous command. Resumes the execution of the inferior program until a breakpoint is encountered, or until the inferior exits.

GDB Command

The corresponding GDB corresponding is `continue'.

Example

-exec-continue
^running
(gdb)
@Hello world
*stopped,reason="breakpoint-hit",bkptno="2",frame={func="foo",args=[],
file="hello.c",fullname="/home/foo/bar/devo/myproject/hello.c",line="13"}
(gdb)

The -exec-finish Command

Synopsis

 -exec-finish

Asynchronous command. Resumes the execution of the inferior program until the current function is exited. Displays the results returned by the function.

GDB Command

The corresponding GDB command is `finish'.

Example

Function returning void.

-exec-finish
^running
(gdb)
@hello from foo
*stopped,reason="function-finished",frame={func="main",args=[],
file="hello.c",fullname="/home/foo/bar/devo/myproject/hello.c",line="7"}
(gdb)

Function returning other than void. The name of the internal GDB variable storing the result is printed, together with the value itself.

-exec-finish
^running
(gdb)
*stopped,reason="function-finished",frame={addr="0x000107b0",func="foo",
args=[{name="a",value="1"],{name="b",value="9"}},
file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
gdb-result-var="$1",return-value="0"
(gdb)

The -exec-interrupt Command

Synopsis

 -exec-interrupt

Asynchronous command. Interrupts the background execution of the target. Note how the token associated with the stop message is the one for the execution command that has been interrupted. The token for the interrupt itself only appears in the `^done' output. If the user is trying to interrupt a non-running program, an error message will be printed.

GDB Command

The corresponding GDB command is `interrupt'.

Example

(gdb)
111-exec-continue
111^running

(gdb)
222-exec-interrupt
222^done
(gdb)
111*stopped,signal-name="SIGINT",signal-meaning="Interrupt",
frame={addr="0x00010140",func="foo",args=[],file="try.c",
fullname="/home/foo/bar/devo/myproject/try.c",line="13"}
(gdb)

(gdb)
-exec-interrupt
^error,msg="mi_cmd_exec_interrupt: Inferior not executing."
(gdb)

The -exec-next Command

Synopsis

 -exec-next

Asynchronous command. Resumes execution of the inferior program, stopping when the beginning of the next source line is reached.

GDB Command

The corresponding GDB command is `next'.

Example

-exec-next
^running
(gdb)
*stopped,reason="end-stepping-range",line="8",file="hello.c"
(gdb)

The -exec-next-instruction Command

Synopsis

 -exec-next-instruction

Asynchronous command. Executes one machine instruction. If the instruction is a function call continues until the function returns. If the program stops at an instruction in the middle of a source line, the address will be printed as well.

GDB Command

The corresponding GDB command is `nexti'.

Example

(gdb)
-exec-next-instruction
^running

(gdb)
*stopped,reason="end-stepping-range",
addr="0x000100d4",line="5",file="hello.c"
(gdb)

The -exec-return Command

Synopsis

 -exec-return

Makes current function return immediately. Doesn't execute the inferior. Displays the new current frame.

GDB Command

The corresponding GDB command is `return'.

Example

(gdb)
200-break-insert callee4
200^done,bkpt={number="1",addr="0x00010734",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8"}
(gdb)
000-exec-run
000^running
(gdb)
000*stopped,reason="breakpoint-hit",bkptno="1",
frame={func="callee4",args=[],
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"}
(gdb)
205-break-delete
205^done
(gdb)
111-exec-return
111^done,frame={level="0",func="callee3",
args=[{name="strarg",
value="0x11940 \"A string argument.\""}],
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"}
(gdb)

The -exec-run Command

Synopsis

 -exec-run

Asynchronous command. Starts execution of the inferior from the beginning. The inferior executes until either a breakpoint is encountered or the program exits.

GDB Command

The corresponding GDB command is `run'.

Example

(gdb)
-break-insert main
^done,bkpt={number="1",addr="0x0001072c",file="recursive2.c",line="4"}
(gdb)
-exec-run
^running
(gdb)
*stopped,reason="breakpoint-hit",bkptno="1",
frame={func="main",args=[],file="recursive2.c",
fullname="/home/foo/bar/devo/myproject/recursive2.c",line="4"}
(gdb)

The -exec-show-arguments Command

Synopsis

 -exec-show-arguments

Print the arguments of the program.

GDB Command

The corresponding GDB command is `show args'.

Example

N.A.

The -exec-step Command

Synopsis

 -exec-step

Asynchronous command. Resumes execution of the inferior program, stopping when the beginning of the next source line is reached, if the next source line is not a function call. If it is, stop at the first instruction of the called function.

GDB Command

The corresponding GDB command is `step'.

Example

Stepping into a function:

-exec-step
^running
(gdb)
*stopped,reason="end-stepping-range",
frame={func="foo",args=[{name="a",value="10"},
{name="b",value="0"}],file="recursive2.c",
fullname="/home/foo/bar/devo/myproject/recursive2.c",line="11"}
(gdb)

Regular stepping:

-exec-step
^running
(gdb)
*stopped,reason="end-stepping-range",line="14",file="recursive2.c"
(gdb)

The -exec-step-instruction Command

Synopsis

 -exec-step-instruction

Asynchronous command. Resumes the inferior which executes one machine instruction. The output, once GDB has stopped, will vary depending on whether we have stopped in the middle of a source line or not. In the former case, the address at which the program stopped will be printed as well.

GDB Command

The corresponding GDB command is `stepi'.

Example

(gdb)
-exec-step-instruction
^running

(gdb)
*stopped,reason="end-stepping-range",
frame={func="foo",args=[],file="try.c",
fullname="/home/foo/bar/devo/myproject/try.c",line="10"}
(gdb)
-exec-step-instruction
^running

(gdb)
*stopped,reason="end-stepping-range",
frame={addr="0x000100f4",func="foo",args=[],file="try.c",
fullname="/home/foo/bar/devo/myproject/try.c",line="10"}
(gdb)

The -exec-until Command

Synopsis

 -exec-until [ location ]

Asynchronous command. Executes the inferior until the location specified in the argument is reached. If there is no argument, the inferior executes until a source line greater than the current one is reached. The reason for stopping in this case will be `location-reached'.

GDB Command

The corresponding GDB command is `until'.

Example

(gdb)
-exec-until recursive2.c:6
^running
(gdb)
x = 55
*stopped,reason="location-reached",frame={func="main",args=[],
file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="6"}
(gdb)

The -file-core-file Command

Synopsis

 -file-core-file corefile

Specify the core file to be debugger.

The -file-exec-and-symbols Command

Synopsis

 -file-exec-and-symbols file

Specify the executable file to be debugged. This file is the one from which the symbol table is also read. If no file is specified, the command clears the executable and symbol information. If breakpoints are set when using this command with no arguments, GDB will produce error messages. Otherwise, no output is produced, except a completion notification.

GDB Command

The corresponding GDB command is `file'.

Example

(gdb)
-file-exec-and-symbols /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx
^done
(gdb)

The -file-exec-file Command

Synopsis

 -file-exec-file file

Specify the executable file to be debugged. Unlike `-file-exec-and-symbols', the symbol table is not read from this file. If used without argument, GDB clears the information about the executable file. No output is produced, except a completion notification.

GDB Command

The corresponding GDB command is `exec-file'.

Example

(gdb)
-file-exec-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx
^done
(gdb)

The -file-list-exec-sections Command

Synopsis

 -file-list-exec-sections

List the sections of the current executable file.

GDB Command

The GDB command `info file' shows, among the rest, the same information as this command. gdbtk has a corresponding command `gdb_load_info'.

Example

N.A.

The -file-list-exec-source-file Command

Synopsis

 -file-list-exec-source-file

List the line number, the current source file, and the absolute path to the current source file for the current executable.

GDB Command

There's no GDB command which directly corresponds to this one.

Example

(gdb)
123-file-list-exec-source-file
123^done,line="1",file="foo.c",fullname="/home/bar/foo.c"
(gdb)

The -file-list-exec-source-files Command

Synopsis

 -file-list-exec-source-files

List the source files for the current executable.

GDB Command

There's no GDB command which directly corresponds to this one. gdbtk has an analogous command `gdb_listfiles'.

Example

N.A.

The -file-list-globals Command

Synopsis

-file-list-globals -file file -shlib image print-values -filter filter_regex -constants constants

List the globals defined in file file and image image. If file is the empty string, then all globals in image are listed, and if both file and image are the empty string, then all globals are listed.

print-values has the same meaning as for `-stack-list-locals'.

filter_regex is optional. If provided, then all statics whose names match the regex will be filtered out.

constants is also optional. If provided, and set to 1, then no const statics will be printed with the exception of const pointers.

GDB Command

There's no GDB command which directly corresponds to this one.

Example

(gdb)
-file-list-exec-source-files
^done,files=[
{file=foo.c,fullname=/home/foo.c},
{file=/home/bar.c,fullname=/home/bar.c},
{file=gdb_could_not_find_fullpath.c}]
(gdb)

If there is more than one file, then the output will be a list of files with the file and the globals as the elements of the list, as in:

(gdb)
-file-list-globals -file "" -shlib gdb --no-values
^done,file=[filename="../../gdb/src/mmalloc/keys.c",globals=[]],file=[filename="../../gdb/src/mmalloc/mmap-sup.c",globals=[]],...]
(gdb)

And if there are more than one shared library, the output will contain a list of images, which will contain a list of files as above, for instance:

(gdb)
-file-list-globals --file "" --shlib "" --no-values
^done,image=[imagename="/usr/lib/dyld"],image=[imagename="/usr/lib/libncurses.5.dylib"],image=[imagename="/usr/lib,image=[imagename="/build/gdb/gdb",file=[filename="../../gdb/src/mmalloc/keys.c",globals=[]],...]]
(gdb)

The -file-list-shared-libraries Command

Synopsis

 -file-list-shared-libraries

List the shared libraries in the program.

GDB Command

The corresponding GDB command is `info shared'.

Example

N.A.

The -file-list-statics Command

Synopsis

 -file-list-statics -file file -shlib image print-values -filter filter_regex -constants constants

List the globals defined in file file and image image. If image is the empty string, then the first occurance of the file file is used.

file also accepts the special cookie *CURRENT FRAME* in which case the currently selected frame is used. You still have to provide an some value for image, but it is ignored.

print-values has the same meaning as for `-stack-list-locals'.

filter_regex is optional. If provided, then all statics whose names match the regex will be filtered out.

constants is also optional. If provided and set to 1, then no const statics will be printed with the exception of const pointers.

GDB Command

There's no GDB command which directly corresponds to this one.

Example

(gdb)
-file-list-statics -file breakpoint.c -shlib gdb --no-values
^done,statics=[{name="overlay_events_enabled"},{name="exception_catchpoint_throw_enabled"},...]
(gdb)

The -file-list-symbol-files Command

Synopsis

 -file-list-symbol-files

List symbol files.

GDB Command

The corresponding GDB command is `info file' (part of it).

Example

N.A.

The -file-symbol-file Command

Synopsis

 -file-symbol-file file

Read symbol table info from the specified file argument. When used without arguments, clears GDB's symbol table info. No output is produced, except for a completion notification.

GDB Command

The corresponding GDB command is `symbol-file'.

Example

(gdb)
-file-symbol-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx
^done
(gdb)

Miscellaneous GDB commands in GDB/MI

The -gdb-exit Command

Synopsis

 -gdb-exit

Exit GDB immediately.

GDB Command

Approximately corresponds to `quit'.

Example

(gdb)
-gdb-exit

The -gdb-set Command

Synopsis

 -gdb-set

Set an internal GDB variable.

GDB Command

The corresponding GDB command is `set'.

Example

(gdb)
-gdb-set $foo=3
^done
(gdb)

The -gdb-show Command

Synopsis

 -gdb-show

Show the current value of a GDB variable.

GDB command

The corresponding GDB command is `show'.

Example

(gdb)
-gdb-show annotate
^done,value="0"
(gdb)

The -gdb-version Command

Synopsis

 -gdb-version

Show version information for GDB. Used mostly in testing.

GDB Command

There's no equivalent GDB command. GDB by default shows this information when you start an interactive session.

Example

(gdb)
-gdb-version
~GNU gdb 5.2.1
~Copyright 2000 Free Software Foundation, Inc.
~GDB is free software, covered by the GNU General Public License, and
~you are welcome to change it and/or distribute copies of it under
~ certain conditions.
~Type "show copying" to see the conditions.
~There is absolutely no warranty for GDB.  Type "show warranty" for
~ details.
~This GDB was configured as
 "--host=sparc-sun-solaris2.5.1 --target=ppc-eabi".
^done
(gdb)

The -interpreter-exec Command

Synopsis

-interpreter-exec interpreter command

Execute the specified command in the given interpreter.

GDB Command

The corresponding GDB command is `interpreter-exec'.

Example

(gdb)
-interpreter-exec console "break main"
&"During symbol reading, couldn't parse type; debugger out of date?.\n"
&"During symbol reading, bad structure-type format.\n"
~"Breakpoint 1 at 0x8074fc6: file ../../src/gdb/main.c, line 743.\n"
^done
(gdb)

The -inferior-tty-set Command

Synopsis

-inferior-tty-set /dev/pts/1

Set terminal for future runs of the program being debugged.

GDB Command

The corresponding GDB command is `set inferior-tty /dev/pts/1'.

Example

(gdb)
-inferior-tty-set /dev/pts/1
^done
(gdb)

The -inferior-tty-show Command

Synopsis

-inferior-tty-show

Show terminal for future runs of program being debugged.

GDB Command

The corresponding GDB command is `show inferior-tty'.

Example

(gdb)
-inferior-tty-set /dev/pts/1
^done
(gdb)
-inferior-tty-show
^done,inferior_tty_terminal="/dev/pts/1"
(gdb)

GDB/MI Stack Manipulation Commands

The -stack-info-frame Command

Synopsis

 -stack-info-frame

Get info on the selected frame.

GDB Command

The corresponding GDB command is `info frame' or `frame' (without arguments).

Example

(gdb)
-stack-info-frame
^done,frame={level="1",addr="0x0001076c",func="callee3",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"}
(gdb)

The -stack-info-depth Command

Synopsis

 -stack-info-depth [ max-depth ]

Return the depth of the stack. If the integer argument max-depth is specified, do not count beyond max-depth frames.

GDB Command

There's no equivalent GDB command.

Example

For a stack with frame levels 0 through 11:

(gdb)
-stack-info-depth
^done,depth="12"
(gdb)
-stack-info-depth 4
^done,depth="4"
(gdb)
-stack-info-depth 12
^done,depth="12"
(gdb)
-stack-info-depth 11
^done,depth="11"
(gdb)
-stack-info-depth 13
^done,depth="12"
(gdb)

The -stack-list-arguments Command

Synopsis

 -stack-list-arguments show-values
    [ low-frame high-frame ]

Display a list of the arguments for the frames between low-frame and high-frame (inclusive). If low-frame and high-frame are not provided, list the arguments for the whole call stack.

The show-values argument must have a value of 0 or 1. A value of 0 means that only the names of the arguments are listed, a value of 1 means that both names and values of the arguments are printed.

GDB Command

GDB does not have an equivalent command. gdbtk has a `gdb_get_args' command which partially overlaps with the functionality of `-stack-list-arguments'.

Example

(gdb)
-stack-list-frames
^done,
stack=[
frame={level="0",addr="0x00010734",func="callee4",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"},
frame={level="1",addr="0x0001076c",func="callee3",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"},
frame={level="2",addr="0x0001078c",func="callee2",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="22"},
frame={level="3",addr="0x000107b4",func="callee1",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="27"},
frame={level="4",addr="0x000107e0",func="main",
file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="32"}]
(gdb)
-stack-list-arguments 0
^done,
stack-args=[
frame={level="0",args=[]},
frame={level="1",args=[name="strarg"]},
frame={level="2",args=[name="intarg",name="strarg"]},
frame={level="3",args=[name="intarg",name="strarg",name="fltarg"]},
frame={level="4",args=[]}]
(gdb)
-stack-list-arguments 1
^done,
stack-args=[
frame={level="0",args=[]},
frame={level="1",
 args=[{name="strarg",value="0x11940 \"A string argument.\""}]},
frame={level="2",args=[
{name="intarg",value="2"},
{name="strarg",value="0x11940 \"A string argument.\""}]},
{frame={level="3",args=[
{name="intarg",value="2"},
{name="strarg",value="0x11940 \"A string argument.\""},
{name="fltarg",value="3.5"}]},
frame={level="4",args=[]}]
(gdb)
-stack-list-arguments 0 2 2
^done,stack-args=[frame={level="2",args=[name="intarg",name="strarg"]}]
(gdb)
-stack-list-arguments 1 2 2
^done,stack-args=[frame={level="2",
args=[{name="intarg",value="2"},
{name="strarg",value="0x11940 \"A string argument.\""}]}]
(gdb)

The -stack-list-frames Command

Synopsis

 -stack-list-frames [ low-frame high-frame ]

List the frames currently on the stack. For each frame it displays the following info:

`level'
The frame number, 0 being the topmost frame, i.e. the innermost function.
`addr'
The $pc value for that frame.
`func'
Function name.
`file'
File name of the source file where the function lives.
`line'
Line number corresponding to the $pc.

If invoked without arguments, this command prints a backtrace for the whole stack. If given two integer arguments, it shows the frames whose levels are between the two arguments (inclusive). If the two arguments are equal, it shows the single frame at the corresponding level.

GDB Command

The corresponding GDB commands are `backtrace' and `where'.

Example

Full stack backtrace:

(gdb)
-stack-list-frames
^done,stack=
[frame={level="0",addr="0x0001076c",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="11"},
frame={level="1",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="2",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="3",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="4",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="5",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="6",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="7",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="8",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="9",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="10",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="11",addr="0x00010738",func="main",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="4"}]
(gdb)

Show frames between low_frame and high_frame:

(gdb)
-stack-list-frames 3 5
^done,stack=
[frame={level="3",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="4",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"},
frame={level="5",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}]
(gdb)

Show a single frame:

(gdb)
-stack-list-frames 3 3
^done,stack=
[frame={level="3",addr="0x000107a4",func="foo",
  file="recursive2.c",fullname="/home/foo/bar/devo/myproject/recursive2.c",line="14"}]
(gdb)

The -stack-list-locals Command

Synopsis

 -stack-list-locals print-values

Display the local variable names for the selected frame. If print-values is 0 or --no-values, print only the names of the variables; if it is 1 or --all-values, print also their values; and if it is 2 or --simple-values, print the name, type and value for simple data types and the name and type for arrays, structures and unions. In this last case, a frontend can immediately display the value of simple data types and create variable objects for other data types when the the user wishes to explore their values in more detail. With an argument of 2, 3, or --create-varobjs, the command makes variable objects for all the variables.

GDB Command

`info locals' in GDB, `gdb_get_locals' in gdbtk.

Example

(gdb)
-stack-list-locals 0
^done,locals=[name="A",name="B",name="C"]
(gdb)
-stack-list-locals --all-values
^done,locals=[{name="A",value="1"},{name="B",value="2"},
  {name="C",value="{1, 2, 3}"}]
-stack-list-locals --simple-values
^done,locals=[{name="A",type="int",value="1"},
  {name="B",type="int",value="2"},{name="C",type="int [3]"}]
(gdb)

The -stack-select-frame Command

Synopsis

 -stack-select-frame framenum

Change the selected frame. Select a different frame framenum on the stack.

GDB Command

The corresponding GDB commands are `frame', `up', `down', `select-frame', `up-silent', and `down-silent'.

Example

(gdb)
-stack-select-frame 2
^done
(gdb)

GDB/MI Symbol Query Commands

The -symbol-info-address Command

Synopsis

 -symbol-info-address symbol

Describe where symbol is stored.

GDB Command

The corresponding GDB command is `info address'.

Example

N.A.

The -symbol-info-file Command

Synopsis

 -symbol-info-file

Show the file for the symbol.

GDB Command

There's no equivalent GDB command. gdbtk has `gdb_find_file'.

Example

N.A.

The -symbol-info-function Command

Synopsis

 -symbol-info-function

Show which function the symbol lives in.

GDB Command

`gdb_get_function' in gdbtk.

Example

N.A.

The -symbol-info-line Command

Synopsis

 -symbol-info-line

Show the core addresses of the code for a source line.

GDB Command

The corresponding GDB command is `info line'. gdbtk has the `gdb_get_line' and `gdb_get_file' commands.

Example

N.A.

The -symbol-info-symbol Command

Synopsis

 -symbol-info-symbol addr

Describe what symbol is at location addr.

GDB Command

The corresponding GDB command is `info symbol'.

Example

N.A.

The -symbol-list-functions Command

Synopsis

 -symbol-list-functions

List the functions in the executable.

GDB Command

`info functions' in GDB, `gdb_listfunc' and `gdb_search' in gdbtk.

Example

N.A.

The -symbol-list-lines Command

Synopsis

 -symbol-list-lines filename

Print the list of lines that contain code and their associated program addresses for the given source filename. The entries are sorted in ascending PC order.

GDB Command

There is no corresponding GDB command.

Example

(gdb)
-symbol-list-lines basics.c
^done,lines=[{pc="0x08048554",line="7"},{pc="0x0804855a",line="8"}]
(gdb)

The -symbol-list-types Command

Synopsis

 -symbol-list-types

List all the type names.

GDB Command

The corresponding commands are `info types' in GDB, `gdb_search' in gdbtk.

Example

N.A.

The -symbol-list-variables Command

Synopsis

 -symbol-list-variables

List all the global and static variable names.

GDB Command

`info variables' in GDB, `gdb_search' in gdbtk.

Example

N.A.

The -symbol-locate Command

Synopsis

 -symbol-locate

GDB Command

`gdb_loc' in gdbtk.

Example

N.A.

The -symbol-type Command

Synopsis

 -symbol-type variable

Show type of variable.

GDB Command

The corresponding GDB command is `ptype', gdbtk has `gdb_obj_variable'.

Example

N.A.

GDB/MI Target Manipulation Commands

The -target-attach Command

Synopsis

 -target-attach pid | file

Attach to a process pid or a file file outside of GDB.

GDB command

The corresponding GDB command is `attach'.

Example

N.A.

The -target-compare-sections Command

Synopsis

 -target-compare-sections [ section ]

Compare data of section section on target to the exec file. Without the argument, all sections are compared.

GDB Command

The GDB equivalent is `compare-sections'.

Example

N.A.

The -target-detach Command

Synopsis

 -target-detach

Disconnect from the remote target. There's no output.

GDB command

The corresponding GDB command is `detach'.

Example

(gdb)
-target-detach
^done
(gdb)

The -target-disconnect Command

Synopsis

 -target-disconnect

Disconnect from the remote target. There's no output.

GDB command

The corresponding GDB command is `disconnect'.

Example

(gdb)
-target-disconnect
^done
(gdb)

The -target-download Command

Synopsis

 -target-download

Loads the executable onto the remote target. It prints out an update message every half second, which includes the fields:

`section'
The name of the section.
`section-sent'
The size of what has been sent so far for that section.
`section-size'
The size of the section.
`total-sent'
The total size of what was sent so far (the current and the previous sections).
`total-size'
The size of the overall executable to download.

Each message is sent as status record (see section GDB/MI Output Syntax).

In addition, it prints the name and size of the sections, as they are downloaded. These messages include the following fields:

`section'
The name of the section.
`section-size'
The size of the section.
`total-size'
The size of the overall executable to download.

At the end, a summary is printed.

GDB Command

The corresponding GDB command is `load'.

Example

Note: each status message appears on a single line. Here the messages have been broken down so that they can fit onto a page.

(gdb)
-target-download
+download,{section=".text",section-size="6668",total-size="9880"}
+download,{section=".text",section-sent="512",section-size="6668",
total-sent="512",total-size="9880"}
+download,{section=".text",section-sent="1024",section-size="6668",
total-sent="1024",total-size="9880"}
+download,{section=".text",section-sent="1536",section-size="6668",
total-sent="1536",total-size="9880"}
+download,{section=".text",section-sent="2048",section-size="6668",
total-sent="2048",total-size="9880"}
+download,{section=".text",section-sent="2560",section-size="6668",
total-sent="2560",total-size="9880"}
+download,{section=".text",section-sent="3072",section-size="6668",
total-sent="3072",total-size="9880"}
+download,{section=".text",section-sent="3584",section-size="6668",
total-sent="3584",total-size="9880"}
+download,{section=".text",section-sent="4096",section-size="6668",
total-sent="4096",total-size="9880"}
+download,{section=".text",section-sent="4608",section-size="6668",
total-sent="4608",total-size="9880"}
+download,{section=".text",section-sent="5120",section-size="6668",
total-sent="5120",total-size="9880"}
+download,{section=".text",section-sent="5632",section-size="6668",
total-sent="5632",total-size="9880"}
+download,{section=".text",section-sent="6144",section-size="6668",
total-sent="6144",total-size="9880"}
+download,{section=".text",section-sent="6656",section-size="6668",
total-sent="6656",total-size="9880"}
+download,{section=".init",section-size="28",total-size="9880"}
+download,{section=".fini",section-size="28",total-size="9880"}
+download,{section=".data",section-size="3156",total-size="9880"}
+download,{section=".data",section-sent="512",section-size="3156",
total-sent="7236",total-size="9880"}
+download,{section=".data",section-sent="1024",section-size="3156",
total-sent="7748",total-size="9880"}
+download,{section=".data",section-sent="1536",section-size="3156",
total-sent="8260",total-size="9880"}
+download,{section=".data",section-sent="2048",section-size="3156",
total-sent="8772",total-size="9880"}
+download,{section=".data",section-sent="2560",section-size="3156",
total-sent="9284",total-size="9880"}
+download,{section=".data",section-sent="3072",section-size="3156",
total-sent="9796",total-size="9880"}
^done,address="0x10004",load-size="9880",transfer-rate="6586",
write-rate="429"
(gdb)

The -target-exec-status Command

Synopsis

 -target-exec-status

Provide information on the state of the target (whether it is running or not, for instance).

GDB Command

There's no equivalent GDB command.

Example

N.A.

The -target-list-available-targets Command

Synopsis

 -target-list-available-targets

List the possible targets to connect to.

GDB Command

The corresponding GDB command is `help target'.

Example

N.A.

The -target-list-current-targets Command

Synopsis

 -target-list-current-targets

Describe the current target.

GDB Command

The corresponding information is printed by `info file' (among other things).

Example

N.A.

The -target-list-parameters Command

Synopsis

 -target-list-parameters

GDB Command

No equivalent.

Example

N.A.

The -target-select Command

Synopsis

 -target-select type parameters ...

Connect GDB to the remote target. This command takes two args:

`type'
The type of target, for instance `async', `remote', etc.
`parameters'
Device names, host names and the like. See section Commands for managing targets, for more details.

The output is a connection notification, followed by the address at which the target program is, in the following form:

^connected,addr="address",func="function name",
  args=[arg list]

GDB Command

The corresponding GDB command is `target'.

Example

(gdb)
-target-select async /dev/ttya
^connected,addr="0xfe00a300",func="??",args=[]
(gdb)

GDB/MI Thread Commands

The -thread-info Command

Synopsis

 -thread-info

GDB command

No equivalent.

Example

N.A.

The -thread-list-all-threads Command

Synopsis

 -thread-list-all-threads

GDB Command

The equivalent GDB command is `info threads'.

Example

N.A.

The -thread-list-ids Command

Synopsis

 -thread-list-ids

Produces a list of the currently known GDB thread ids. At the end of the list it also prints the total number of such threads.

GDB Command

Part of `info threads' supplies the same information.

Example

No threads present, besides the main process:

(gdb)
-thread-list-ids
^done,thread-ids={},number-of-threads="0"
(gdb)

Several threads:

(gdb)
-thread-list-ids
^done,thread-ids={thread-id="3",thread-id="2",thread-id="1"},
number-of-threads="3"
(gdb)

The -thread-select Command

Synopsis

 -thread-select threadnum

Make threadnum the current thread. It prints the number of the new current thread, and the topmost frame for that thread.

GDB Command

The corresponding GDB command is `thread'.

Example

(gdb)
-exec-next
^running
(gdb)
*stopped,reason="end-stepping-range",thread-id="2",line="187",
file="../../../devo/gdb/testsuite/gdb.threads/linux-dp.c"
(gdb)
-thread-list-ids
^done,
thread-ids={thread-id="3",thread-id="2",thread-id="1"},
number-of-threads="3"
(gdb)
-thread-select 3
^done,new-thread-id="3",
frame={level="0",func="vprintf",
args=[{name="format",value="0x8048e9c \"%*s%c %d %c\\n\""},
{name="arg",value="0x2"}],file="vprintf.c",line="31"}
(gdb)

GDB/MI Tracepoint Commands

The tracepoint commands are not yet implemented.

GDB/MI Variable Objects

Motivation for Variable Objects in GDB/MI

For the implementation of a variable debugger window (locals, watched expressions, etc.), we are proposing the adaptation of the existing code used by Insight.

The two main reasons for that are:

  1. It has been proven in practice (it is already on its second generation).
  2. It will shorten development time (needless to say how important it is now).

The original interface was designed to be used by Tcl code, so it was slightly changed so it could be used through GDB/MI. This section describes the GDB/MI operations that will be available and gives some hints about their use.

Note: In addition to the set of operations described here, we expect the GUI implementation of a variable window to require, at least, the following operations:

Introduction to Variable Objects in GDB/MI

The basic idea behind variable objects is the creation of a named object to represent a variable, an expression, a memory location or even a CPU register. For each object created, a set of operations is available for examining or changing its properties.

Furthermore, complex data types, such as C structures, are represented in a tree format. For instance, the struct type variable is the root and the children will represent the struct members. If a child is itself of a complex type, it will also have children of its own. Appropriate language differences are handled for C, C++ and Java.

When returning the actual values of the objects, this facility allows for the individual selection of the display format used in the result creation. It can be chosen among: binary, decimal, hexadecimal, octal and natural. Natural refers to a default format automatically chosen based on the variable type (like decimal for an int, hex for pointers, etc.).

The following is the complete set of GDB/MI operations defined to access this functionality:

@multitable @columnfractions .4 .6

  • Operation @tab Description
  • -var-create @tab create a variable object
  • -var-delete @tab delete the variable object and its children
  • -var-set-format @tab set the display format of this variable
  • -var-show-format @tab show the display format of this variable
  • -var-info-num-children @tab tells how many children this object has
  • -var-list-children @tab return a list of the object's children
  • -var-info-type @tab show the type of this variable object
  • -var-info-expression @tab print what this variable object represents
  • -var-show-attributes @tab is this variable editable? does it exist here?
  • -var-evaluate-expression @tab get the value of this variable
  • -var-assign @tab set the value of this variable
  • -var-update @tab update the variable and its children In the next subsection we describe each operation in detail and suggest how it can be used.

    Description And Use of Operations on Variable Objects

    The -var-create Command

    Synopsis

     -var-create {name | "-"}
        {frame-addr | "*"} expression
    
    This operation creates a variable object, which allows the monitoring of a variable, the result of an expression, a memory cell or a CPU register. The name parameter is the string by which the object can be referenced. It must be unique. If `-' is specified, the varobj system will generate a string "varNNNNNN" automatically. It will be unique provided that one does not specify name on that format. The command fails if a duplicate name is found. The frame under which the expression should be evaluated can be specified by frame-addr. A `*' indicates that the current frame should be used. expression is any expression valid on the current language set (must not begin with a `*'), or one of the following:

    Result

    This operation returns the name, number of children and the type of the object created. Type is returned as a string as the ones generated by the GDB CLI:
     name="name",numchild="N",type="type"
    

    The -var-delete Command

    Synopsis

     -var-delete name
    
    Deletes a previously created variable object and all of its children. Returns an error if the object name is not found.

    The -var-set-format Command

    Synopsis

     -var-set-format name format-spec
    
    Sets the output format for the value of the object name to be format-spec. The syntax for the format-spec is as follows:
     format-spec ==>
     {binary | decimal | hexadecimal | octal | natural}
    

    The -var-show-format Command

    Synopsis

     -var-show-format name
    
    Returns the format used to display the value of the object name.
     format ==>
     format-spec
    

    The -var-info-num-children Command

    Synopsis

     -var-info-num-children name
    
    Returns the number of children of a variable object name:
     numchild=n
    

    The -var-list-children Command

    Synopsis

     -var-list-children [print-values] name
    
    @anchor{-var-list-children} Return a list of the children of the specified variable object and create variable objects for them, if they do not already exist. With a single argument or if print-values has a value for of 0 or --no-values, print only the names of the variables; if print-values is 1 or --all-values, also print their values; and if it is 2 or --simple-values print the name and value for simple data types and just the name for arrays, structures and unions.

    Example

    (gdb)
     -var-list-children n
     ^done,numchild=n,children=[{name=name,
     numchild=n,type=type},(repeats N times)]
    (gdb)
     -var-list-children --all-values n
     ^done,numchild=n,children=[{name=name,
     numchild=n,value=value,type=type},(repeats N times)]
    

    The -var-info-type Command

    Synopsis

     -var-info-type name
    
    Returns the type of the specified variable name. The type is returned as a string in the same format as it is output by the GDB CLI:
     type=typename
    

    The -var-info-expression Command

    Synopsis

     -var-info-expression name
    
    Returns what is represented by the variable object name:
     lang=lang-spec,exp=expression
    
    where lang-spec is {"C" | "C++" | "Java"}.

    The -var-show-attributes Command

    Synopsis

     -var-show-attributes name
    
    List attributes of the specified variable object name:
     status=attr [ ( ,attr )* ]
    
    where attr is { { editable | noneditable } | TBD }.

    The -var-evaluate-expression Command

    Synopsis

     -var-evaluate-expression name
    
    Evaluates the expression that is represented by the specified variable object and returns its value as a string in the current format specified for the object:
     value=value
    
    Note that one must invoke -var-list-children for a variable before the value of a child variable can be evaluated.

    The -var-assign Command

    Synopsis

     -var-assign name expression
    
    Assigns the value of expression to the variable object specified by name. The object must be `editable'. If the variable's value is altered by the assign, the variable will show up in any subsequent -var-update list.

    Example

    (gdb)
    -var-assign var1 3
    ^done,value="3"
    (gdb)
    -var-update *
    ^done,changelist=[{name="var1",in_scope="true",type_changed="false"}]
    (gdb)
    

    The -var-update Command

    Synopsis

     -var-update [print-values] {name | "*"}
    
    Update the value of the variable object name by evaluating its expression after fetching all the new values from memory or registers. A `*' causes all existing variable objects to be updated. The option print-values determines whether names and values, or just names are printed in the manner described for @xref{-var-list-children}.

    Example

    (gdb)
    -var-assign var1 3
    ^done,value="3"
    (gdb)
    -var-update --all-values var1
    ^done,changelist=[{name="var1",value="3",in_scope="true",
    type_changed="false"}]
    (gdb)
    


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